Aerodynamic Safing Approach for the 2001 Mars Odyssey Spacecraft During Aerobraking

摘要

The 2001 Mars Odyssey spacecraft represents the third generation of aerobraking designs, following Magellan's pioneering aerobraking demonstration at Venus and Mars Global Surveyor's planned operational aerobraking at Mars. Aerobraking provides significant advantages for interplanetary spacecraft by reducing the size of the required propulsion system and propellant load, thereby allowing larger payloads for the same launch mass. However, aerobraking is not without risk; relatively small command errors or brief inattention to the highly variable atmospheric dynamics can lead to disaster. This paper describes how the 2001 Mars Odyssey aerobraking design and operations managed the inherent aerodynamics-related risks of aerobraking. We describe the configuration changes Odyssey used during aerobraking orbits and how the operations team managed those configurations. We present a detailed vehicle dynamics model derived for Odyssey's aerobraking safe-mode configuration, as well as the predicted attitude response during aerobraking safing events. Contingency procedures were developed before aerobraking and included an option to "pop-up" out of the atmosphere if aerobraking operations began to endanger spacecraft health and safety. We describe the criteria and decision-making process for commanding popup maneuvers. Finally, flight results from Odyssey's aerobraking experience are presented including an assessment of the aerodynamic safing approach in response to the highly variable atmospheric conditions.